Hair styling compositions are desired that provide both good hold (i.e., the ability to hold hair in place) and good shine (i.e., the ability to give hair a shiny appearance). Additionally, clarity (translucent appearance) of the hair styling composition prior to application is aesthetically important to consumers.
Typically, hair styling compositions include one or more polymers which serve as the hair fixative. While there are many polymers that provide good hold in hair styling compositions, some of them negatively impact other properties such as shine or clarity.
Hair styling compositions also typically include an aqueous solvent which is a mixture of water and one or more volatile organic solvents. The class of volatile organic compounds (VOCs) which are liquid at 25° C. and one atmosphere pressure are generally useful as volatile organic solvents in hair spray compositions. Because hair styling compositions are sometimes sprayed, it is desirable that any polymers used in the composition dissolve fully in the aqueous solvent. Further, for proper spraying, it is desirable that a solution of any polymers used in the composition should have viscosity that is not too high.
Where a hair styling composition is to be applied in an aerosol spray, the aqueous solvent also includes one or more propellants, which may be volatile non-organic compounds or VOCs and are gaseous at 25° C. and one atmosphere pressure. For example, without limitation, it is known to use carbon dioxide, propane, isobutane, dimethyl ether and tetrafluoroethane, among other materials, as the aerosol propellant for such compositions.
It is also desirable that the hair styling composition be stable (i.e., that none of the ingredients settles while the composition is in storage). It is known that as the volatile organic compound (VOC) content of a composition containing certain polymers increases, a haze appears, and increases, in the composition, due to insolubility and precipitation of the polymer from aqueous solvent. This haze is aesthetically unpleasing to consumers.
Thus, selecting the types and proportions of ingredients for hair styling compositions is very important and can be difficult. It is desired to provide polymers which have good hold characteristics, without negatively impacting the levels of shine and clarity in hair styling compositions. Typical high VOC-containing hair fixative polymers can result compositions that are hazy. The present invention is believed to improve polymer compatibility in such compositions, thereby, resulting in improved clarity (i.e., reduced haze).
One approach to improving the water solubility of carboxylated vinyl polymeric hair spray resins in alcohol hydrocarbon propellant systems has been to neutralize at least a portion of the available carboxyl functionalities of the resins, as described in U.S. Pat. No. 4,192,861, using alkaline reagents.
U.S. Pat. No. 4,315,910 describes aerosol hair spray compositions used in aerosol metal containers that contain polymer, including, for example, styrene/maleic anhydride polymers, as well as carbon dioxide or hydrocarbon-alcohol propellants and 1-15% by weight water. It is asserted in U.S. Pat. No. 4,315,910 that addition of the water to this composition improved shelf stability and solubility of the polymer in these compositions compared to anhydrous compositions using carbon dioxide or hydrocarbon-alcohol in aerosol metal containers.
It is also known to improve the clarity of non-aerosol, gel hair styling compositions containing silicone grafted co-polymers by neutralization with organic or inorganic neutralizer or mixtures thereof. GB 2 291 893 A describes an aqueous/alcohol hair styling gel containing a silicone-containing polycarboxylic acid polymer and selected organic neutralizing agents that is claimed to have further improved clarity as well as non-sticky in-use feel and easy brush-out characteristics.
An object of the present invention was to identify neutralizing agents which render the polymers more compatible with the VOCs used in hair styling compositions.